Well I set it off on Sunday, sadly I didn't check back here to heed Graz' good advice
Because I use a sachet of yeast with sweetener i'm pretty much stuck to making 25L so in it all went with Pectolase and almost 1kg sugar, leaving about 2" clear at the top. The apple cider i'm used to making isn't very volatile at all for some reason, but I came home Monday eve to find the Pineapple merrily bubbling over after it had popped the lid off the bucket.
Not too much of a problem I thought as I picked it up and sat it on the mop bucket so it could drip into there while I got my dinner.
5 mins later I hear the sound of a mop bucket collapsing and the whoosh as about 6 or 7 litres of brew goes all over the floor. That's my Monday eve sorted then i'm thinking as I reach for the mop.
So it now has 5" of head space and it was still sick on the floor in the night!
The problem I have is I don't know what I've lost in terms of sugar and yeast, I don't know whether it was sat on the bottom and i've lost mainly juice or what (I heat the sugar to dissolve it before adding initially).
So not off to a great start, but we'll see what happens and i'll report back.
So what is it that makes some brews more volatile than others?